Chemical conjunctivitis, also known as toxic conjunctivitis, is an acute inflammation of the eye’s surface caused by exposure to a chemical agent. This condition is not contagious, unlike the common viral or bacterial forms of pink eye, as it results directly from tissue irritation or damage. The severity of the injury depends entirely on the substance and the duration of contact, making it a genuine medical emergency. Prompt intervention is necessary, as corrosive agents can cause irreversible damage to the delicate ocular structures in minutes.
Common Causes of Chemical Exposure
Chemical conjunctivitis arises from contact with a spectrum of agents, ranging from simple irritants to highly caustic substances. Mild irritants, such as the chlorine found in swimming pools, soap residue, or minor cosmetic splashes, typically cause temporary discomfort and superficial redness. These exposures are usually self-limiting once the substance is flushed from the eye.
More severe injuries, however, result from exposure to caustic acids or alkalis, which are categorized as true chemical burns. Alkali substances, such as those found in drain cleaners (lye), oven cleaners, or ammonia, are particularly dangerous because they penetrate the eye tissue rapidly through a process called liquefaction necrosis. This deep penetration can cause extensive damage to the cornea and internal structures.
Acidic agents, like battery acid or industrial cleaners, tend to be less penetrating because they cause a coagulation necrosis, which creates a protective barrier that limits deeper injury. High-concentration household products and industrial chemicals require immediate emergency intervention.
Identifying the Symptoms
The onset of symptoms is immediate following exposure and varies based on the corrosiveness of the chemical. Intense, often extreme, pain is a common initial sign, frequently accompanied by a feeling that a foreign object is trapped in the eye. The severity of the pain does not always correlate with the potential for long-term damage, as some highly damaging alkali agents can dull nerve endings, temporarily masking the true extent of the burn.
Visible signs include a profound redness of the conjunctiva, the clear membrane covering the white of the eye. A particularly concerning sign is limbal ischemia, where the blood vessels near the edge of the cornea appear blanched or white instead of red. This indicates damage to the limbal stem cells, which are responsible for corneal repair, and is a strong predictor of a poor prognosis. Other symptoms involve copious tearing, significant swelling of the eyelids, and blurred or decreased vision.
Essential First Aid (Immediate Response)
The single most important action following chemical exposure to the eye is immediate and extensive irrigation, or flushing. This must begin within seconds of the injury, using any non-caustic fluid available, such as tap water or saline solution. Do not delay irrigation to search for a specific eyewash station or professional medical help; the goal is to dilute and wash away the chemical before it can cause deeper tissue damage.
The injured person must hold their eyelid open and allow a continuous, gentle stream of water to flow across the eye. It is important to tilt the head so the water flows away from the unaffected eye, preventing cross-contamination. Irrigation should continue uninterrupted for at least 15 to 20 minutes, or even longer for strong alkali exposures, before transport to a medical facility.
While flushing, a bystander should immediately contact emergency medical services or poison control to report the exact chemical involved. The injured person should remove contact lenses immediately, as they can trap the chemical agent against the eye’s surface.
Professional Medical Care and Recovery
Upon arrival at a medical facility, the initial priority remains the continuation of irrigation until the chemical is completely neutralized. Medical personnel periodically check the eye’s surface pH using special test strips, aiming for a neutral reading of 7.4. If the pH remains abnormal, irrigation continues, often with large volumes of fluids or specialized solutions administered through a device called a Morgan lens.
Once the eye’s pH is stabilized, a full ophthalmic examination assesses the extent of the damage, particularly to the cornea and limbus. Treatment involves prescription medications such as topical broad-spectrum antibiotics to prevent secondary infection. Cycloplegic drops are administered to paralyze the ciliary muscle, which reduces painful spasms and promotes patient comfort.
Corticosteroids may be prescribed for inflammation control; however, their use is cautious and tapered quickly due to the risk of corneal melting. The long-term prognosis depends largely on the severity of the initial burn, especially the degree of limbal ischemia observed. Mild injuries may heal fully within days, while severe burns can lead to corneal scarring, glaucoma, or permanent vision loss, often requiring complex surgical procedures.